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	/*
	* Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package com.sun.crypto.provider;

	import java.io.ObjectStreamException;
	import java.nio.ByteBuffer;
	import java.nio.CharBuffer;
	import java.nio.charset.Charset;
	import java.util.Arrays;
	import java.security.MessageDigest;
	import java.util.Locale;
	import java.security.KeyRep;
	import java.security.GeneralSecurityException;
	import java.security.NoSuchAlgorithmException;
	import java.security.spec.InvalidKeySpecException;
	import javax.crypto.Mac;
	import javax.crypto.SecretKey;
	import javax.crypto.spec.PBEKeySpec;

	/**
	* This class represents a PBE key derived using PBKDF2 defined
	* in PKCS#5 v2.0. meaning that
	* 1) the password must consist of characters which will be converted
	* to bytes using UTF-8 character encoding.
	* 2) salt, iteration count, and to be derived key length are supplied
	*
	* @author Valerie Peng
	*
	*/
	final class PBKDF2KeyImpl implements javax.crypto.interfaces.PBEKey {

	static final long serialVersionUID = -2234868909660948157L;

	private char[] passwd;
	private byte[] salt;
	private int iterCount;
	private byte[] key;

	private Mac prf;

	private static byte[] getPasswordBytes(char[] passwd) {
	Charset utf8 = Charset.forName("UTF-8");
	CharBuffer cb = CharBuffer.wrap(passwd);
	ByteBuffer bb = utf8.encode(cb);

	int len = bb.limit();
	byte[] passwdBytes = new byte[len];
	bb.get(passwdBytes, 0, len);

	return passwdBytes;
	}

	/**
	* Creates a PBE key from a given PBE key specification.
	*
	* @param key the given PBE key specification
	*/
	PBKDF2KeyImpl(PBEKeySpec keySpec, String prfAlgo)
	throws InvalidKeySpecException {
	char[] passwd = keySpec.getPassword();
	if (passwd == null) {
	// Should allow an empty password.
	this.passwd = new char[0];
	} else {
	this.passwd = passwd.clone();
	}
	// Convert the password from char[] to byte[]
	byte[] passwdBytes = getPasswordBytes(this.passwd);
	// remove local copy
	if (passwd != null) Arrays.fill(passwd, '\0');

	this.salt = keySpec.getSalt();
	if (salt == null) {
	throw new InvalidKeySpecException("Salt not found");
	}
	this.iterCount = keySpec.getIterationCount();
	if (iterCount == 0) {
	throw new InvalidKeySpecException("Iteration count not found");
	} else if (iterCount < 0) {
	throw new InvalidKeySpecException("Iteration count is negative");
	}
	int keyLength = keySpec.getKeyLength();
	if (keyLength == 0) {
	throw new InvalidKeySpecException("Key length not found");
	} else if (keyLength < 0) {
	throw new InvalidKeySpecException("Key length is negative");
	}
	try {
	this.prf = Mac.getInstance(prfAlgo, SunJCE.getInstance());
	this.key = deriveKey(prf, passwdBytes, salt, iterCount, keyLength);
	} catch (NoSuchAlgorithmException nsae) {
	// not gonna happen; re-throw just in case
	InvalidKeySpecException ike = new InvalidKeySpecException();
	ike.initCause(nsae);
	throw ike;
	} finally {
	Arrays.fill(passwdBytes, (byte)0x00);
	}
	}

	private static byte[] deriveKey(final Mac prf, final byte[] password,
	byte[] salt, int iterCount, int keyLengthInBit) {
	int keyLength = keyLengthInBit/8;
	byte[] key = new byte[keyLength];
	try {
	int hlen = prf.getMacLength();
	int intL = (keyLength + hlen - 1)/hlen; // ceiling
	int intR = keyLength - (intL - 1)*hlen; // residue
	byte[] ui = new byte[hlen];
	byte[] ti = new byte[hlen];
	// SecretKeySpec cannot be used, since password can be empty here.
	SecretKey macKey = new SecretKey() {
	private static final long serialVersionUID = 7874493593505141603L;
	@Override
	public String getAlgorithm() {
	return prf.getAlgorithm();
	}
	@Override
	public String getFormat() {
	return "RAW";
	}
	@Override
	public byte[] getEncoded() {
	return password;
	}
	@Override
	public int hashCode() {
	return Arrays.hashCode(password) * 41 +
	prf.getAlgorithm().toLowerCase(Locale.ENGLISH).hashCode();
	}
	@Override
	public boolean equals(Object obj) {
	if (this == obj) return true;
	if (this.getClass() != obj.getClass()) return false;
	SecretKey sk = (SecretKey)obj;
	return prf.getAlgorithm().equalsIgnoreCase(
	sk.getAlgorithm()) &&
	MessageDigest.isEqual(password, sk.getEncoded());
	}
	};
	prf.init(macKey);

	byte[] ibytes = new byte[4];
	for (int i = 1; i <= intL; i++) {
	prf.update(salt);
	ibytes[3] = (byte) i;
	ibytes[2] = (byte) ((i >> 8) & 0xff);
	ibytes[1] = (byte) ((i >> 16) & 0xff);
	ibytes[0] = (byte) ((i >> 24) & 0xff);
	prf.update(ibytes);
	prf.doFinal(ui, 0);
	System.arraycopy(ui, 0, ti, 0, ui.length);

	for (int j = 2; j <= iterCount; j++) {
	prf.update(ui);
	prf.doFinal(ui, 0);
	// XOR the intermediate Ui's together.
	for (int k = 0; k < ui.length; k++) {
	ti[k] ^= ui[k];
	}
	}
	if (i == intL) {
	System.arraycopy(ti, 0, key, (i-1)*hlen, intR);
	} else {
	System.arraycopy(ti, 0, key, (i-1)*hlen, hlen);
	}
	}
	} catch (GeneralSecurityException gse) {
	throw new RuntimeException("Error deriving PBKDF2 keys");
	}
	return key;
	}

	public synchronized byte[] getEncoded() {
	return key.clone();
	}

	public String getAlgorithm() {
	return "PBKDF2With" + prf.getAlgorithm();
	}

	public int getIterationCount() {
	return iterCount;
	}

	public synchronized char[] getPassword() {
	return passwd.clone();
	}

	public byte[] getSalt() {
	return salt.clone();
	}

	public String getFormat() {
	return "RAW";
	}

	/**
	* Calculates a hash code value for the object.
	* Objects that are equal will also have the same hashcode.
	*/
	public int hashCode() {
	int retval = 0;
	for (int i = 1; i < this.key.length; i++) {
	retval += this.key[i] * i;
	}
	return(retval ^= getAlgorithm().toLowerCase(Locale.ENGLISH).hashCode());
	}

	public boolean equals(Object obj) {
	if (obj == this)
	return true;

	if (!(obj instanceof SecretKey))
	return false;

	SecretKey that = (SecretKey) obj;

	if (!(that.getAlgorithm().equalsIgnoreCase(getAlgorithm())))
	return false;
	if (!(that.getFormat().equalsIgnoreCase("RAW")))
	return false;
	byte[] thatEncoded = that.getEncoded();
	boolean ret = MessageDigest.isEqual(key, thatEncoded);
	Arrays.fill(thatEncoded, (byte)0x00);
	return ret;
	}

	/**
	* Replace the PBE key to be serialized.
	*
	* @return the standard KeyRep object to be serialized
	*
	* @throws ObjectStreamException if a new object representing
	* this PBE key could not be created
	*/
	private Object writeReplace() throws ObjectStreamException {
	return new KeyRep(KeyRep.Type.SECRET, getAlgorithm(),
	getFormat(), getEncoded());
	}

	/**
	* Ensures that the password bytes of this key are
	* erased when there are no more references to it.
	*/
	protected void finalize() throws Throwable {
	try {
	synchronized (this) {
	if (this.passwd != null) {
	java.util.Arrays.fill(this.passwd, '\0');
	this.passwd = null;
	}
	if (this.key != null) {
	java.util.Arrays.fill(this.key, (byte)0x00);
	this.key = null;
	}
	}
	} finally {
	super.finalize();
	}
	}
	}

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